docs: def get_compression_type(self, file_name):
          """
              Determine compression type for a given file using its extension.
  
              :param file_name: a given file name
              :type file_name: str
          """
  
          ext = os.path.splitext(file_name)[1]
  
          if ext == '.gz':
              self.ctype = 'gzip'
          elif ext == '.bz2':
              self.ctype = 'bzip2'
          elif ext in ('.xz', '.lzma'):
              self.ctype = 'lzma'
          else:
              self.ctype = None